This quantity is maximized by weight vectors in a “canonical” method for analyzing this quantity. Separation indices accounting for measurement error are used in a “disattenuation” for this quantity. A term proportional to “one minus this quantity squared, all over 2n” is added to this quantity to obtain its “adjusted” form. (-5[1])One rank coefficient (-5[1])for this quantity is equal to [read slowly] “one minus twice the number of discordant pairs divided by n choose two.” This quantity for some X and Y is equal to their covariance divided by the product (10[1])of their (10[2])standard deviations. Pearson’s coefficient for this quantity (10[1])takes values between (10[1])negative 1 and 1 and is symbolized (10[1])r. For 10 points, name this statistical quantity that measures the relation (10[2])between two variables and is often mistaken with causation. ■END■ (10[1])